Polymer–colloid composites represent an attractive class of hybrid materials in which one can tailor their properties by exploiting the individual and collective properties of both components 1,2,3,4.

In Fig. 1e we show the time dependence of B measured when a bipolar electric pulse E(t) (where t is time; black line) is applied to the same samples shown in Fig. 1a, showing normal (green line) and ...